Explosive



is ammonium nitrate.

Patented Ma 4, 1937 uN T o STATES EXPLOSIVE Milton F. Lindsley, Jr Kings Mills, Ohio, assignor to The King Powder Company, Kings Mills, Ohio, a corporation of Ohio No Drawing. Application January 26, 1935, Serial No. 3,644

9 Claims.

This invention relates to explosives and particularly to those adapted for blasting either in mining or quarrying or for similar purposes. Such an explosive may likewise be used in high explosive shells. The invention is particularly directed to an explosive adapted to be set off by a detonating cap as distingushed from a fuse. The explosive of this invention comprises a mixture of high explosive, fuel and oxidizing agents. The physical consistency of the composition is such that it may be used in granulated, pellet or moulded form. The high explosive employed This material is very hygroscopic and tends to take on moisture very readily. Also, in the past the size of the granules of a finished explosive has been determined by the size of the ammonium nitrate crystals.

One object of ammonium nitrate explosive which is substantially not hygroscopic and is suitable for blast-- Another object of the invention is to provide an ammonium nitrate explosive which is non-hygroscopic in nature and which has a physical consistency adapting it for use in the various physical forms suitable or desirable for blasting.

Still another object of the invention is to produce an explosive of the nature specified, the sensitivity of which is augmented by a secondary coating which may also increase the water resistivity of the product.

In'the explosive of this invention 20 to 80% ammonium nitrate is employed. An additional oxidizing agent, such as sodium nitrate, may be used, the preferred quantity being 10 to 45%.

Other oxidizing agents, such as potassium nitrate, barium nitrate or the like, may be used in whole or in part in place of the sodium nitrate. Approximately 1 to 10% sulphur is used to accelerate the speed of the explosion.

Though supplemental fuels may be incorporated in the explosive, the main fuel is a substance called tar char. This material is the residue from the stills used in distilling coal tar or petroleum products and comprises in general 92 to 98% fixed carbon. Tar char is obtained from the residue left in stills after the heavy distilate has been removed from coal tar, by heating such residue in the absence of air to drive off all volatile matter. The tar char has three functions in the explosive. First of all it serves as a fuel, secondly as a binder, and thirdly as a waterproofing agent.- As a fuel it combines chemically with the oxidizing agents and adds to the force of the explosion. As a binding agent it imparts to the admixture a consistency which permits it to be compacted under pressure, such as 2500to 3500 pounds per square inch, into grains, pellets, sticks or grindable cake. As a water-proofing agent it serves to protect the ammonium nitrate the invention is to produce an' from the moisture of the atmosphere and thereby creates a substantially non-hygroscopic explosive. The tar char may be used in quantities of from 5 to 16% of the total weight of the explosive.

In addition to the materials mentioned, paraffln may be added to the composition in an amount up to 5% of the total weight. The paraflin assists the tar char as a binder and waterproofing agent and'likewise in the grain form has the peculiar characteristic of imparting greater speed of explosion to the admixture.

One composition which has been found to be highly useful as a blasting explosive is as follows:

' Percent Ammonium nitrate 55.0 Sodium nitr 32.3 Tar char 8.7 Paraflin 215i Sulphur 1.5

This composition is approximately equivalent to 40% dynamite in strength and is therefore more powerful than black powder. Since no nitroglycerine is used, common nitroglycerine toxicity is absent and the material consequently does not induce headache from this source before or after ignition.

If desirable, the sensitivity of the explosive may be augmented by various exterior coatings. Preferably, any coating applied should be of nonhygroscopic nature.

Among the materials which may be used for such purpose are nitroglycerine, nitroglycerine colloided with nitrocellulose, or solutions of other explosive materials which are compatible with nitroglycerine. Aluminum dust may be used alone or as an addition to any of the above coatings. It has the characteristic of improving the sensitivity of the explosive when used aloneor in combination with other coating materials, and,

furthermore, improves the free flowing properties of the explosive.

One composition suitable for coating the explosive of this invention comprises:

Grains coated as described may be used as free flowing powder, or may be further subjected to pelleting or moulding operations.

In manufacturing an explosive of the specified ingredients, the constituting components are finely divided, mixed until homogeneous, and then compressed under a pressure such as 2500 to 3500 pounds per square inch. This pressure may be applied in molds which impart to the alternative method of making pelleted or molded Having described my invention,.I desire to be limited bnly by the ensuing claims:

1. An explosive suitable for blasting, said explosive comprising, ammonium nitrate, oxidizing agents, sulphur, and tar char.

2. A granular, free flowing explosive suitable for blasting comprising, ammonium nitrate, oxidizing agents, par sulphur and tar char-.

3. An explosive suitable for blasting p rposes, said explosive comprising, 20-80% ammonium nitrate, 10-45% sodium nitrate, 546% tar char, 0-5% paraflin and 1-4% sulphur.

4. A granular, free flowing explosive suitable for blasting purposes, said explosive,-eomprising 20-80% ammonium nitrate, 10-45% sodium nitrate, 546% tar char, .5-5% paraiiin and 1-4% sulphur.

5. An explosive suitable for bl sting p po s.

said explosive comprising, an admixture compacted under pressure into physical form suitable for blasting, said admixture comprising, ammonium-nitrate, tar char, and an oxidizer.

6. An explosive suitable for blasting purposes, said explosive comprising, an admixture compacted under pressure into physicalv form suitable for blasting, said admixture comprising, ammonium nitrate, tar char, an oxidizer and sulphur.

7. An explosive suitable. for blasting purposes, said explosive comprising, an admixture compacted under pressure'into physical form suitable for blasting, said admixture comprising, ammonium nitrate, tar char, an oxidizer, sulphur and paraflln.

8. The method 01' rendering an ammonium nitrate explosive more suitable for blasting purtrate granular explosive, said method, compris- MILTON F. INDSLEY, JR. 

